New Delhi: With Railways a "big headache" to efforts to make the country open defecation free, Rural Development Minister Jairam Ramesh on Tuesday offered that his Ministry would bear half the cost of retrofitting eco-friendly bio-toilets in all 50000 coaches in five years.

The total cost for retrofitting bio-toilets in all coaches would be about Rs 500 crores.

Ramesh, who also holds the portfolio of Drinking Water and Sanitation, said that at present only nine trains with 436 coaches are fitted with bio-toilets, while 4,000 coaches are produced annually which could be fitted with new bio-toilets developed by Defence Research & Development Organisation (DRDO).

"...What I have offered to Railway Board Chairman is that we will bear 50 per cent cost of retrofitting each on the 50000 coaches with the DRDO biodigesters in 4 to 5 years time," he told reporters here after meeting Railway Board Chairman Vinay Mittal and senior board officials at his Ministry on Tuesday.

The Ministry of Drinking Water and Sanitation would bear its 50 percent cost for retrofitting to provide Indian Railways, which ferries 11 million passengers daily, with hygenic sanitation.

During his meeting, Ramesh also asked the Railway Board officials to run a Nirmal Bharat Express, fitted with bio-toilets, which will go in various railwaylines to spread the message of sanitation and hygiene.

In these bio-toilets, the human waste is treated by bacteria which is benign to the humans. This bacteria converts human waste into water and gases (methane and CO2).

The gases escape into atmosphere and treated waste water is discharged after chlorination. Human waste, thus, does not fall on the tracks.

Railways have claimed that this system not only improves the environment and hygiene but also helps in preventing corrosion to coach and track components.

Speaking in the capital last month, Ramesh had said Railways was "another big headache for us" on the issue of ending manual scavenging and open defecation.

The Rural Development Ministry has launched a campaign to end open defecation in 10 years.